Enable threads support

This patch defines the macros and adds the hashtable template required for
enabling threads support in cxx library.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Teodora Serbanescu <teo.serbanescu16@gmail.com>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Export __dso_handle

Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Fix some of the compiling warnings

This patch removes the "unused-parameter" warnings generated by the origin code
and the multiple definition warnings for _LIBCPP_BUILDING_LIBRARY and
_LIBCPPABI_VERSION macros.

Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Add features.h

When threads are enabled, cxx library includes a 'features.h' header in its
'include/__config' header from origin. The header introduced by this patch
includes the 'sys/features.h' header from newlib.

Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Add exported symbols

This patch adds the mangled functions to the
exportsyms.uk. Due to the high number of symbols
this is a separate patch.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Initial port of libcxx to Unikraft

This is our initial port of libcxx to Unikraft as an external
library. Libc is requiered for it to work. The dependency list
should contain: ...:$(UK_LIBS)/libunwind:
$(UK_LIBS)/compiler-rt:$(UK_LIBS)/libcxxabi:$(UK_LIBS)/libcxx:
$(UK_LIBS)/newlib:...

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Add .gitignore

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Initial commit (empty)